Transmission method of mobile station for random access channel diversity

Abstract

A transmission method performed by a mobile station for random access channel (RACH) burst transmission diversity gain is provided. According to the method, a variety of combinations of a time switching transmit diversity (TSTD) technique, a frequency hopping technique, and a power ramping technique that are robust against fading channel environments are applied to transmission of an RACH burst, thereby increasing the probability of detecting an RACH signature of a base station. Also, by using the transmission parameters (subband frequencies, transmission antennas, power, etc.) which are used for successful transmission of an RACH burst, for transmission of a successive user packet data, reliable transmission of the successive user packet data can be performed.

1. A transmission method performed by a mobile station of obtaining random access diversity, the method comprising:
 (a) transmitting a random access channel (RACH) burst signal to a base station, by using a transmission antenna selected from among multiple transmission antennas; 
 (b) if an acknowledgement (ACK) response to the RACH burst signal from the base station is received, transmitting user packet data by using the transmission antenna which is used for transmission of the RACH burst signal; 
 (c) if a non-acknowledgement (NACK) response to the RACH burst signal from the base station is received, transmitting a new RACH burst signal to the base station, by using a transmission antenna different from the previous transmission antenna; and 
 (d) if an ACK has not been received from the base station and all the multiple transmission antennas have been used to transmit a RACH burst signal to the base station, newly setting a transmission power higher than the previously set transmission power, and then, returning to the step (a). 
 
     
     
       2. The method of  claim 1 , wherein the transmission power of the user packet data is set based on the transmission power which is used for the transmission of the RACH burst signal of which the ACK is generated. 
     
     
       3. The method of  claim 1 , wherein the step (a) comprises:
 (a1) generating the RACH burst signal, by performing orthogonal frequency division multiple access (OFDMA) modulation of the RACH burst signal so that the RACH burst signal can be loaded on a set subband; and 
 (a2) processing the RACH burst signal and then, transmitting the RACH burst signal through the selected transmission antenna. 
 
     
     
       4. The method of  claim 3 , wherein the step (a2) comprises:
 up-converting the RACH burst signal into a radio frequency (RF) signal with a preset transmission power; and 
 selecting a transmission antenna through which the up-converted RACH burst signal is to be transmitted. 
 
     
     
       5. The method of  claim 3 , wherein the step (a2) comprises:
 selecting a transmission antenna through which the RACH burst signal is to be transmitted; and 
 up-converting the RACH burst signal into an RF signal with a preset transmission power. 
 
     
     
       6. The method of  claim 1 , wherein the RACH burst signal includes a signature sequence for identifying a mobile station which attempts random access. 
     
     
       7. The method of  claim 1 , wherein the RACH burst signal includes information on at least one of a user identifier or a resource request for setting up a call. 
     
     
       8. The method of  claim 3 , wherein the OFDMA modulation includes discrete Fourier transform-spread (DFT-S) OFDMA modulation. 
     
     
       9. A transmission method performed by a mobile station of obtaining random access diversity, the method comprising:
 (a) transmitting an RACH burst signal to a base station, by using a transmission antenna selected from among multiple transmission antennas and a set subband; 
 (b) if an ACK of the RACH burst signal from the base station is received, transmitting user packet data by using the transmission antenna and the subband which are used for transmission of the RACH burst signal; 
 (c) if a NACK of the RACH burst signal from the base station is received, transmitting a new RACH burst signal to the base station, by using a transmission antenna different from the previous transmission antenna or a subband different from the previous subband; and 
 (d) if an ACK has not been received from the base station and all combinations of the transmission antennas and subbands have been used to transmit a RACH burst signal to the base station, newly setting a transmission power higher than the previously set transmission power, and then, returning to the step (a). 
 
     
     
       10. The method of  claim 9 , wherein the transmission power of the user packet data is set based on the transmission power which is used for the transmission of the RACH burst signal of which the ACK is generated. 
     
     
       11. The method of  claim 9 , wherein the step (a) comprises:
 (a1) generating the RACH burst signal, by performing OFDMA modulation of the RACH burst signal so that the RACH burst signal can be loaded on the set subband; and 
 (a2) processing the RACH burst signal and then, transmitting the RACH burst signal through the selected transmission antenna. 
 
     
     
       12. The method of  claim 11 , wherein the step (a2) comprises:
 up-converting the RACH burst signal into an RF signal with a preset transmission power; and 
 selecting a transmission antenna through which the up-converted RACH burst signal is to be transmitted. 
 
     
     
       13. The method of  claim 11 , wherein the step (a2) comprises:
 selecting a transmission antenna through which the RACH burst signal is to be transmitted; and 
 up-converting the RACH burst signal into an RF signal with a preset transmission power. 
 
     
     
       14. The method of  claim 9 , wherein the RACH burst signal includes a signature sequence for identifying a mobile station which attempts random access. 
     
     
       15. The method of  claim 9 , wherein the RACH burst signal includes information on at least one of a user identifier or a resource request for setting up a call.